This disclosure relates to a diffusion bonding machine and method, for example, for manufacturing hollow blades.
Some hollow fan blades are manufactured by diffusion bonding two halves to one another. The blades are constructed from a titanium alloy, for example. The blade halves typically include features, such as ribs, that must precisely mate with one another to ensure desired bonding between the ribs. Uniform heating is essential to avoid introducing misalignment of the ribs due to temperature distortion. Similarly, after bonding, the dies must be uniformly cooled to avoid temperature induced distortion. Typically, two die sets are stacked vertically onto one another to increase the number of blades processed.
The halves are bonded together by radiantly preheating the blade within an enclosed set of dies before applying pressure sufficient to bond the halves to one another. The die sets are also heated during pressing. The configuration of the stacked dies requires conduction of heat from the outer sides of the die sets to the interior of the die sets where the blades are located. As a result, a very lengthy heating time is required.
One type of diffusion bonding machine includes three stations. The stack of die sets is loaded into the first station and preheated. Pressure is applied to the die stack at a second station and the die sets continue to be exposed to heat at the second station. Once bonding is complete, the die stack is transferred to a third station where the dies are cooled and then unloaded from the third station. Throughout the manufacturing process at the various stations, the die sets remain closed and stacked relative to one another.